Tuesday, June 30, 2009

42-03-02

As the years pass, you discover seedlings that grab your attention for one reason or another. Perhaps one stands out as very different from its siblings, or one might have an architecture feature you like, or superior disease resistance. While it might not be immediately apparent what purpose such a seedling might serve, it is wise to hang on to it and culture it and wait for its purpose to be revealed. I know that sounds a bit too mystical to be appropriate for something as systematic and planned as rose hybridizing, but the concept has meaning.

Take 42-03-02 illustrated here, for example. It is a selfing of the Moore breeder 0-47-19. It bears a striking resemblance to the Moore Hybrid Wichurana except that it has deeper coloring and is a 2.5 foot rounded shrub, always in flower. As its parent is a known diploid, I am assuming this is also and so I now use it in breeding specifically to further diploid breeding lines. It accepts a wide range of pollens and makes seed with about 50% viability in most cases. Testing the limits of its ability this year, I put some strikingly dissimilar pollens on it, including a 'Schneezwerg' F2 seedling and 'Scabrosa'. I have also used my R. foliolosa on it, and all of these pollens have resulted in healthy, fat hips.

My recommendation to breeders is that when a seedling grabs your attention for some reason, pay attention. It might prove to be a stepping stone at some point down the line, It might not tell you what its purpose is today, but it might turn out to be meaningful in a few years time and you'll be glad you kept it.

Hi Paul, as a rule I'm partial to dark green foliage. That said, there is something beautiful here. Bright lime, chartuese foliage, it is incredible. That showcasing the hot pink....well, it's a winner and welcome in my rose bed! Enjoy your work Paul as we enjoy watching! A fan, Rod

You know I love the idea of using 'Scabrosa' because I used it a lot last season myself. I also find it interesting that when you used 'Scabrosa' as the pollen parent on a wichurana based plant it took... any pollen from plants with a strong wichurana influence, including quite a few polyantha like 'The Fairy' and 'Baby Faraux', put onto 'Scabrosa' failed for me last season. The closest I was able to get to stick was 'Magic Carrousel' which has wichurana 3 generations back and it produced very little seed (only about 10 seeds per hip) compared to the other tetraploid crosses with 'Scabrosa' that produced up to 92 seeds per hip. I think I will also try your idea this coming season and use it (and 'Ann Endt') the other way around on the wichurana based varieties that failed last season but which set a prodigious amount of OP hips (though, again, taking your advice I am test germinating lots of these OP wichurana hyrbid seeds to assess germinability... so maybe I should reserve such decisions until after I see their strike rate).

I try not to use the "purebred" Rugosas as seed parents, partly because they self-pollinated long before the bloom opens, making it difficult to get your pollen to do what you want. I do occasionally use one as a seed parent but I wash the stigmas with a spray of water after emasculation, allowing it to dry and then pollinating, to ensure that it is MY pollen that is ferilizing the ovaries.

Why my Wichurana hybrid is accepting such a wide variety of pollens I don't know, but it has taken almost anything I have put on it. But then, I do try to limit my selections to diploids, and that may play a role.

George,I don't think you can say that this is "miniaturization" in action, but simply a dwarfing like what we've seen happen in the Polyanthas and other compact shrubs. There is a direct relationship between continuous blooming habit and dwarfness: its as though the plant is coded to bloom rather than grow infrastructure. And so, what you sometimes get is a short, compact shrub that is almost always in flower. I have seen plants of this type emerge from 0-47-19 fairly often: they bloom while still very young and rarely have the same vigor as their more vegetatively-oriented siblings.

What mechanism is responsible for manifesting this type of plant is anyone's guess.